Factory sealed Ansco 4x5 sheet film from the stone age

200 speed......25 sheets. BW Press film. Expired March 1968, still has the factory seal on it.

If I exposed these at say, ISO 16 or 25 would I get a usable image?

Or rather 6 to 12, maybe even 3. It ain't going to get faster in its old age.

Only one way to find out. Probably you want to use a fog-reducing restrainer in your developer, though I've never tried that as I don't use such antediluvian film.

I gues it depends on the film itself.
For example, I had the chance to put my hands on 8 rolls of Kodak Verichrome Pan in 620 format (with an expiry date of september 1973) that I used with my Kodak Tourist. This film is rated 125ASA. I shot my rolls at the 125ISO and to only overexposed by 1 stop and it came out fine!

I'll crack the seal on it tonight and load it on two film holders.

Development.....don't know when my darkroom is almost finished I just need chemistry and some trays and hangers and what not.