If all the engine covers were there, outside the engine looked ok and the engine wasn't seized, then and only then if you have a lot of money behind you to probably replace most of the internals and you had nothing else to do then go for it..
If you buy it for parts, then you may pick up something of value and get your money back. Depending on what needs to be done to the engine, price may go from a couple of hundred and run in to the thousands. Also depends if you want an engine with all the tricks such as big bore 895 or over 1000 cc kit, crank, rods, pistons, seals.....the list keeps going to do it properly. Port & polish, HD valve springs, retainers, cam... If you have a bank of parts to start with then it may save you some cash.
Bottom line, a lot of variables. I'd tend towards no.