To begin with, this timing chain system is NOTHING like a Domestic V8.

Secondly, you could get an idea about the condition of the chain guides by simply pulling off the valve cover and look at the top one that you can see. While the cover is off it wouldn't take too much more trouble to do a preliminary chain stretch check.

The accurate check involves a dial indicator and some very specific information and measurements. You can, however, get an idea of chain stretch by simply rotating the crankshaft clockwise, ALWAYS CLOCKWISE never backwards on these, until TDC is exactly at the pointer on the crankshaft damper. Look to see if the notch in the cam washer behind the cam gear is aligned with the notch on the cam tower. If you see it and it is perfectly aligned, you have virtually no stretch. If the cam mark is not in sight, simply rotate the crankshaft one full turn until TDC is aligned and then check the mark.

Good luck,