Parts manuals are available from the dealer, or they can be obtained from third parties such as on Ebay. They generally are not cheap from either the dealer or other sources- minimum of $65.
I have also noticed that you can pick up microfiche copies of those manuals pretty cheap sometimes (between $5 and $20).
It's helpful to already know the parts numbers, but those are things the dealer should be able to readily look up- I know that the dealer in my area (KC Bobcat) has no problems as long as you have the serial number because there are changes between early and late S/N 630s. I also had no problem when using Intermountain Bobcat for my 630, so generally no problem as a rule.
If you have a choice, I would see if you could find a different dealer in your area or a different location as they obviously are not sure what they are doing with older machines.