The images for many of the Dell models are identical. There are only about 3 or 4 different images. I've never tried to find out about actual differences.
It could be a good strategy to pick the latest image (by date), as it is likley to have the lastest updates and drivers.
@Yaron The links are generated on a first-come first-served basis. I just checked the logs to find out when the Hebrew version usually unlocks, but sad to say, it hasn't managed to unlock for more than a year now.
Competition to grab Windows 7 in one of the rarely requested languages is quite high. The best chance to get your download really is to try as often as possible, starting March 1, until no more links can be generated (usually around the 3rd or 4th day of the month).
Also try the other Windows 7 editions (Home, Ultimate, COEM). You can easily convert the disc to Win 7 Pro.
Alternatively, if you don't mind the Dell branding, you can download a multi-lingual Dell disc. There is no restriction on those downloads, and they work on all PC brands.