Yeah, always good to verify the cam position; but....
- highly unlikely a 103 chain will stretch enough in 200k miles to appreciably affect cam timing (very rugged) - unless it's been worked on and reassembled wrong.
- still gotta find that exact piston TDC, and not knowing exactly where the damper/tab marks should align makes it a bit of a guess. The best way is to use a piston stop and go forwards-measure, backwards-measure, like when degreeing a new cam. But, I don't think the experts recommend turning a 103engine backwards, as it really stresses the chain tensioner.

I glanced thru the book, and the timing spec for the 103 at idle is 7-11 with the vacuum line either attached or plugged. Easy to check, though, just check the timing and then plug it and see if it changes.

One commet, years ago I did unplug my resistor, and the timing at idle did not change. It also didn't change at 2500 RPM in neutral. I assume it might cause a difference under load.
Comment - I left the resistor in and switched to regular fuel about 12 years ago - zero issues.

DG