I recently found a used Telecaster neck at my local pawn shop, and I'm having some
difficulty figuring out what model it came from. I've found a few sites with information on identifying Strat necks by the headstock design, truss rod orientation, etc., but nothing on Telecaster necks.

It's a 25.5" scale, all maple, 4-bolt neck with non-locking grover tuners(might not be
stock). The truss adjustment is at the headstock, the nut slot is cut straight across (you can slide the nut freely from side to side), and it appears to be constructed of two pieces of maple, as you can see a seam running lengthways, just under the side fret markers.

The headstock has the standard silver with black trim Fender logo, with "TELECASTER" offset under it. The only other marking left on this was an "OK" stamp between the two furthest bolt-on holes.

So, is there any way to identify approximately how old this thing is, or what model
Telecaster it came from? Also, I'm planning to order a thinline style body from
www.warmoth.com for use with this neck. Any known issues with matching a neck like this up with a warmoth body?

I've uploaded a few pictures on photobucket:

From your description, I would say that the neck was most probably manufactured somewhere between '73 and '76.
I really didn't expect it to be quite so old. The finish is pretty yellowed, but I kind of figured it might be some sort of vintage reissue sort of thing. Any idea if it's an American, Japanese or Mexican made neck? Either way, I got it for US $60 tax included, so I'm happy with it.