If you are planning on using the rifle and if it is mechanically sound, I’d say clean the bore.  Enjoy your shooting.  Get to know the feel of the rifle.  Shoot more.  Old oil and DNA will wait.  Clean the interior at your leisure.  I suggest getting to know the rifle prior to cleaning so that after reassembling it, if it drags, lags, complains, you know you did something amiss.  If it feels slightly slicker to operate, you know it is dandy and ready for more exercise.

If you are planning on firing it, and then keeping it in the safe–Someone else should offer advice.  I don’t know much about collecting without shooting often.