Well, no Specialized Allez will EVER be worthy of being an "investment". Is it worth $375? Well, for that price, I'd expect a more modern geartrain (at least 9-sp), with smooth-running hubs, balanced and trued wheels, decent tires, replacement brifters, and a good paint job. And it would have to be a frame in my size, as well.
I see a decent 105 rear derailleur, with a bit of a good-quality ferruled rim. You'll have to look at the rest, but it looks like it could be worth that price, depending on where you live (NY,SF, LA, Seattle, etc. it would be a steal. Lincoln, NE, maybe not...)
I'd say the bike is worth $375 IF it fits. A triple crank with that 9 speed cassette should provide plenty of gear range. 9 speed parts are getting hard to find, so DON'T change any of the drivetrain parts UNLESS you plan to upgrade everything. As long as the drivetrain wears together, you should have no problems.
Inspect the aluminum frame for cracks, inspect the rims around the spoke holes for same. You will have to buy your pedal system of choice, and maybe a new saddle.
If you're not mechanically inclined, it would be worth taking the bike to a bike shop for a tune-up after purchase.
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