Yes, manufacturers always give you an approximate number (here), plus lens marks on photography lenses are never accurate (a lens that breathes makes anything else impractical).
I would say that's the case. When I set my 28-70 to 50mm and then just under 35 in APS-c the FOV is really close. If the exif reads 32mm its a hair wider, if it reads 34mm its just slightly narrower, I can't get it to show 33mm and who knows how accurate the cheap kit lens markings. I don't have any other way to measure. If you do the math in stills resolution, FF is 4240px wide, APS-c is 2768px multiplied by a 1.532 crop is 4240.5px. So its a little more than 1.5.
