Based on your description of the rifle the price you paid may be just about right. The 32nd Edition of Blue Book of Gun Values shows $250 as the reasonable price for a 788 in 70% condition. The 788 was introduced in 1967 and discontinued in 1983. The rifle was made only for short action cartridges, .222 Rem through .308 Win. The stock had a Monte Carlo comb, no cheekpiece, and no checkering. As stated in your post, the rifle had detachable box magazines. The trigger of the 788 was both good and bad, but the good out-weighed the bad. The trigger was not particularly smooth or light, but was very fast, and this fact made the rifle very accurate. I vaguely recall stories/rumors etc. that Remington discontinued the 788 because its accuracy and low price were significant advantages when compared to Remington's own 700 rifles (the ADL and BDL) which competed in the same market for retail sales. In short, shooters bought the 788 rather than the more expensive (and profitable) 700. I have a 788 in .223. I glass bedded the action and under the chamber. I free-floated the barrel. I shortened the stock, deepened the flutes above and behind the grip and installed a red Ruger recoil pad (from another rifle) and finally, refinished the stock. And I have a 3 x 9 scope on it. The rifle will put hand loads into a 1/2 to 1 inch group at 100 yards consistently. Enjoy your "new" 788.
NRA Life Member - RMEF Life Member - Vietnam Vet