It may be possible to see this category.
But reasonable price is Big question.
Paperwork is also not easy for such old bike.
Keeping in India is possible but running it in different places is not possible.
Locally can move nearby only.
You have to try to find out by yourself only.
Buying would be possible but u won't be able to get the paperwork done in at least the metro cities of India. The RTO won't allow the transfer of ownership. Only option would be to make affidavits and take and give undertaking to the owner or the seller. Once restored u can only use it to run in the back lanes or if u get a classic certificate somehow than on special days or events.
I guess you are planning to do this, because it is easier to import classic motorcycles into other countries than the current ones. You can try to get in touch with Lali Singh. He does that for quite a few foreigners, including taking care of the hassle of getting it legally registered in India and shipping out of here.