Welcome back!!!
Your question really depends on how high the standard you set...I understand a lot of people will say: add this and that in order to unleash LP12's potentials. I would rather put it this way...if a TT has to be tweaked to perform its best, does it mean the basic configurations are not good enough? Is it worth to spend that much for a fully modded TT? Is there any alternatives for the same costs?
Another question is: are you familiar with TTs with this kind of "springy" suspensions? IMHO, LP12 is NOT for someone who looks for "set and forget". In fact, an LP12 requires certain experience on fine-tuning its "sound"(and it really has its sonic signature!). So your relevant experience is another key! Or you have do some research on this issue.
If this used LP12 doesn't cost you much, and still has its re-sale value, your buying action seems to be justified. However, we are audiophiles, we are always tempted to "tweak this and that" if it doesn't sound "right to our ears", (some may say that's fine if we could have some satisfactions over the process.) buying a used TT may involve hidden repair costs if it really need an overhaul to function normally. In this case, the initial cost may be low but the running costs may be high.
Another factor involving substantial cost is "buying records". I would not suggest you to spend too much on your TT/arm/cart/phono if you are not planning to buy lots of LPs.
Does your budget include cart and phono stage? Or do you have any now?
Good luck
Dan