I just bought a Deluxe of of a well known internet auction site. . I was surprised to see that the serial number was not a DZ, which for years signified the Deluxe models. In fact my serial is an all numeric one, beginning with 1.

I tried to look it up on Guitar Dater (http://www.guitardaterproject.org/fender.aspx), but that did not return any results.

Does anyone know when Fender changed the serial numbers on the Am Deluxes? Where can I date this particular guitar?

My US Deluxe has it's serial No beginning with DN.
Mind you I have had her for about 12 years since new.

I just punched her details into the dater linked above in your post and I get the following which works out perfectly:

This guitar is from the American Deluxe Series
made at the Corona Plant (Fender), USA
in the Year(s): 1998 - 1999

Snowy

Almost all the guitar dater sites have yet to catch up with Fender's new serial number system that started last year (2010).

For USA production models Fender used an all-numeric number starting with a "10" for the first 3-4 months of 2010. It sounds like that is what you have. I suppose they found that the "10" font was too similar to the font of the other digits because about May or so of last year they switched to using a "US10" prefix; you can clearly see the "US10" is in a different font than the other digits. Also when Fender started using the "10" they dropped the additional "D" prefix on the American Deluxes and the "S" prefix on the USA-made Artist series instruments (except the Eric Johnsons which use serial numbers on the neck plate).

MIM serial numbers change over about mid-year so they were still using "MZ9" serial numbers until about July; at that point the MIMs switched to an "MX10" prefix. And just like the USA models they no longer use an "S" prefix on the MIM Artist models.

Thanks

That casts a doubt over the model I got though...
I wanted the new Deluxe model (N3 pickups, new S-1 switching and compunded radius), which Fender started producing in March 2010.
Whilst I can clearly see that the guitar has the N3 pickups, I am not sure it has the compounded fretboard radius (which is what I really really wanted).

How can I know for sure it's got the upgraded switching system or the compounded radius?

No, you got the new one. If you've got the N3 pickups, you've got the new one. Another way to tell is to look at your fingerboard markers - if you have a rosewood board it should have pearl dots, if you have a maple board it should be "black pearl" dots. All the older American Deluxes had abalone dots (they are pearly but have bluish-greenish hue to them).

Actually Fender didn't start producing them in March 2010; they announced them and immeditately started shipping them in March 2010. In fact, they did the first run of these guitars in late 2009; they carry "DZ9" serial numbers because they were made in December - I saw a few of these new on the shelves locally last spring. I don't know why Fender decided to hold the American Deluxes until March last year; they normally introduce new models at the winter NAMM show (usually mid-late January) but I guess they wanted the American Specials to have the spotlight as the only new model last year.

The old joke is that "NAMM" stood for "Not Available; Maybe in May" because a company would show a new guitar's prototypes at the show in January but they don't have any to ship to dealers until May or June. To combat that Fender has typically done a full production run of their new guitars so they can immediately fill orders at NAMM. They did that for the 2010-spec American Deluxes. They have been doing this for several years; I had a 2004-spec American Deluxe that I got in March 2004 but it had a "DZ3" (2003) serial number and a standard neck plate instead of the "50th Anniversary" neck plate because it was from this first production run.

Hope that helps and puts your mind to rest.

Thanks. Everything you've pointed out is spot on. The markers are indeed darker and the fretboard feels flatter in the higher registers.

On a separate note, I can honestly say this is the best Strat I have ever played / owned. It just oozes quality and it's so comfortable to play. Great sound from those N3 pickups and finally an S1 that is not just a gimmick (love all the sounds). Well done, Fender!