Well I guess my problem is telling the older EB's from the newer ones. And the regular EB from the EB P48. Hmm. I'll have to do some research on serial numbers. Thanks for the link.
There really aren't any newer EB's. They did do a reissue in a very small quantity, but other than that there hasn't been an EB manufactured since about 1982 or so. The EB P48 models say "P48" on the front, so assuming you can read
you should be able to weed those out. Original EB's are all silver. The P48 have black on one side of the grill.
If all else fails, look through the grill. If the capsule has a brass ring it's an older EB. If it's got a white ring it may still be an EB, but it doesn't have the brass capsule.
One thing to keep in mind though - just because it's got a brass capsule doesn't mean it's going to sound good. Those capsules have not been manufactured in over 30 years. Even back then AKG's quality control was not exactly what the standard is today. So it's perfectly possible (and in some cases, LIKELY) to have a newer teflon capsule that sounds better than a brass one.
The first models of the EB used the CK12 brass capsules, left over from the C12 and 412 models before it. When AKG finally ran out they switched to the teflon capsule in the EB's. Apparently if you do manage to find a brass capsule model, you should NEVER send it back to AKG. They have been known to "upgrade" the older capsules to the newer ones, often without notifying the owner until it's too late.
Good luck. FWIW, brass or teflon, I think the EB model is the best sounding 414 they ever made. There's just something about it.