The rubbers looked compressed as the bikes they originally came on had shorter lower legs, and that would stretch them out more. So just take them off and put the original "dirt bike" style dust covers back on and you're in business. Probably...maybe...
Hope there is nothing nasty lurking under the covers.
PS: and the springs may be sacked. The fork oil likely needs to be changed anyway.
to answer your original question, there are no external markings on the tubes to identify. You would need to disassemble and look at the internals.
