The prior two posts are proof positive you should take internet advice with a grain of salt.

There is no way in hell you can or should run 28 tires on wheels of that era and width.

They will not seat properly even if they can be mounted at all.

The fact it is a 3 mm difference is totally irrelevant. A 28 mm tire will likely size 29 or 30 nowadays.

I am a mechanical engineer I should know.