Just get some ford parts book, they list the years a part fits---there is one called "the green book", 28-48, and there are others that can be found cheaper, 28-37,
A good companion to a set of parts books are the OSI (Obsolete-Supersede-Interchange ) catalogs. These were issued in between the price books to show what some parts were superseded or replaced by. Parts catalogs only give the last known part number at the time of printing. These also show when a part went obsolete. Not all parts were changed, some stayed the same until they went obsolete. It's just an additional reference book to have if you're chasing down NOS parts. Anyone who has done Ford parts, will swear by the books. I know I used them constantly in my career. Nowadays, the pricing is all online and they update everything daily.
These books appear on Ebay now and then.
I couldn't agree with Barry more on the Ford O.S.I catalog. the few I have are nearly worn out. However they are more useful for 1955 and later as that is when Ford really seemed to start changing and super-ceding numbers.
I have a few from the early 50's and they cover alot from the 40's and earlier. The early stuff is listed after the later stuff because of the shorter prefix. I wish I could find more of them, but they printed 4-6 per year back then. Most were tossed when the new one came out. In the 70's, I would keep them for one year and throw them in the trash. Wish I had kept them now! A fairly complete set of these appeared on microfiche in the 70's or 80's. Last dealership I worked at had it and we specialized in finding NOS stuff that other dealers couldn't find.