Checking the timing takes about as long as hooking up the timing light and pointing it at the tab. In most jurisdictions that require emission testing, checking and recording the base timing is usually part of the test.

It looks like you have a 124 with a 102 engine. Not sure about your engine, but the 103 engines of that vintage do not have adjustable base timing, and I suspect yours is the same. The complete timing map is controlled electronically by the EZL ignition module using the TDC #1 pulse from the magnetic pickup sensor on the front torsional damper as a reference signal.

Reading the diagnostic memory is a couple of minutes of buttom pushing, but if you don't have a "check engine" light, there are probably no stored fault codes.

What makes you think there is a problem?

Duke