Mounting an original Polyglas

I was lucky to come across a date coded Polyglas for my Duster that looks like it's never been on a car. There are no signs of dry rot or cracking and I want to mount it on my date coded rim. This tire is for my spare. SHOW ONLY and will never be on the car. My question is, when I go to get it mounted should I tell them to just fill enough air to seal the bead? Bottom line I don't want a 50 year old tire blowing up on anyone. Does anyone have any experience with this? Thank you.