Welcome! Since no one has taken a shot at this yet, I will even tho I don't have an early '80s H&R shotgun, I do have an 80's model 158 30-30 barrel on a modern frame and I know others that have done the opposite, I think you'll find it is just like modern production frames and barrels, a barrel may or may not fit, some will fit fine, others will take a lot of work to get them fitted, but it can be done. If the barrel you try has a threaded forend stud, it most likely will work just fine when properly fitted, see the FAQs and Help sticky barrel fitting info.
Tim
