Premier stopped building preinternational sized drums around 1968 so that won't be an issue as that is a later 70s - early 80s drum. Even if it were preinternational, the 14" size is the same either way so there are no issues with 14" drums. You can fit any 14" hoops you wish and the tension rods are standard size too. I get most of my drum parts from drumfactorydirect.com. They have a great selection of parts and great service.
When buying tension rods, it is important to remember that you measure them from the bottom of the head to the end of the thread. You don't include the head of the rod in your measurement.
If you want to upgrade the strainer and butt, indedrum.com has a very nice adjustable strainer and butt plate that should fit and will definitely be better than the stock ones. They also sell the butt plate separately. Just make sure you get the version with the horizontal holes and not the one with the vertical holes.
https://www.indedrum.com/strainers-butt-plates/