Those tires look almost new! Great tread and condition.
I've purchased replacement Pro Vector 701's for the Honda 350x. The replacements were labeled as "P/V 701" as opposed to the original all spelled out "Pro Vector 701".
I've not seen replacement 200X tires, but I'd assume that they did the same there. I'd agree that if those are spelled out "Pro Vector" then they are original. If you really want to know, check out the date code stamped on the tire. There are decoders for this. The rules for the date codes changed (can't remember if it was after 2000, or some other date). But the old codes can be read to see if these were made in the 80's.
As for use and care: I say ride them if you're riding in low risk areas. Avoid pavement, avoid trails with stumps along the side, avoid fields that have been brush-hogged which leaves lots of short pointy sticks (from the sapling trees that have been chopped off).
If you have a 2nd set of rims, look for some cheapies to mount up for bombing around in risky areas.
Also, store the machine with no weight on tires. My reason for this is that if the tires go flat, you won't be at risk of creating lots of stress cracks from sitting all flat.
- Frank
1984 200ES Big Red
1985 350X (x2)
1986 350X
1986 250SX
1984 Auto-X
1984 ATC70
1985 ATC70