Yea, looks like an International . If so should take a pretty healthy tire for your gravel rides! I had my Mondia set up for mild dirt roads for a while . It was fun taking some of the ag roads by the orchards. Not really gravel , just dirt roads . I was able to squeeze 27” x 1 1/4” tires that measured 1.39” when inflated . Your frame reminds me of my ‘73 Mondia.

Very similar to my eye