Todd:
On what site and where did you find the 76?
As the owner of two short scale Alembics (a Signature Standard and a Series I) as well as two other Series I basses, I totally concur with Keith and Jazzy regarding the pricing. I've paid between $1,600 (1980 that needs a complete refurbish) - $4,000 (looks to be the younger brother of the 1979 Koa you found at Reverb in perfect shape; great electronics; no finish checking). I think that if you're patient you'll be able to find a Series I shorty birthed anywhere from the late 70s to mid-80s for somewhere in the neighborhood of $3,500-4,500.
Personally, I really don't see the differences between the I and II to be significant enough to spend the extra $$$$ for the II. The Series I does everything I could ever think of asking a bass to do (and a lot more). Things to keep in mind are: (1) has the electronics upgrade been done (this could or could not be important based on where you'll be playing your bass and the individual instrument itself); (2) does it come with the original power supply and cord (these can add significantly to the cost if you need to purchase them); (3) does it look like the bass has been taken care of; (4) what is the sellers return policy?
If you cannot get to the bass and play it yourself, I'd ask the current owner to make you a video of him or her playing the bass and demonstrating the functionality of each of its PUs, the Q switches, controls etc. It's not a good as playing the bass itself but it will allow to to get an idea as to whether both PUs work and the electronics are sound. If the seller wont do this, I'd pass on that bass. I'd also ask for additional photos of the bass that provide a better picture of the condition of the PUs, fretboard, body and neck.