If you have part numbers you can check E bay, or parts voice, there are a few still out there but after 50 years even NOS will need some work.
Yes, specially if they were originally packaged in a smaller box! Folds and bends are not too bad for a year or so, but THEN with extended time, they can "take a set" and be difficult to remove when the part is taken out of the box, by observation.
Back in the later 1970s, our '72 Newport Royal 4dr sedan had had an issue since new, where at a certain road speed and conditions, the lh frt door would shake. When it did that, the weatherstrip would let in more wind noise and such. I found out I could still get a new weatherstrip from Chrysler, so I ordered one locally.
When it arrived, I knew I had just wasted my money. Why? New part, should be better. The box it was packed in was about 9"x9"x3". The rubber item was "wadded up" nicely to fit. When I took it out of the box, the weatherstrip was twisted and tangled and did not easily "unwind". It might have taken a week in the warm TX sun, marinaded in rubber restorer to become CLOSE to being able to be used. On so many weatherstrips, they use a molded convex surface to seal to the body, but when those molded areas are collapsed and wrinkled in the packaging process, then stay that way for years, not useable.
NOTHING against any NOS weatherstrip vendors, but "buyer beware".
Just my experiences,
CBODY67