"backwards" is a relative term as not all machines are made to have the flywheel turn the same. I beleive a lot of "Franklin" badge machines were made by Domestic (White) and I know White turn opposite Singers, and now most turn like Singer did, it's very possible that it is turning correctly. Most I've seen, if you turn them the wrong way, the feed dogs and hook move backwards so it can't form a stitch.
If it is a VS machine, they do have a bit of a hitch in them, but I don't think it moves the fabric, you see it more in the needle.
BTW - how old is your vintage machine? If it's a zigzag machine, then it may have a type of stretch stitch, but they did not start making machines like that until knits became popular, so like 60's -70's. If it's a straight stitch only machine, it should not be doing anything like that. If your machine has reverse, the reverse may be the problem. I had a Singer 15-91 that the reverse lever didn't want to stay where it was put, so it would move around with each stitch and that caused some strange stitching. the spring tension part had lost too much of it's tension.