1978 450 SL 186k miles California

got it back from a smog check and this is what it reported:

%CO2 %O2
15 MPH 13.6 1.2
25MPH 13.7 1.0

HC CO NO
MAX GP MEAS MAX GP MEAS MAX GP MEAS
191 384 [B]835[B/] 1.25 2.85 0.05 1277 2425 824
159 335 [B]554[B/] 1.05 2.65 0.03 1137 2225 716


Missed the fuel cap integrity test too. Would a bad fuel cap make the HCs put me in the gross polluter levels? I'll change it out of course, but don't want to shell out $70 for another smog check and advance my chances of taking it to a smog referee.

I checked lots of the old posts too, sounds like a bad cat or not hot enough before the test.

Am I on the right track?
Do I have a bad mass airflow sensor or do I hav one for that matter?

TIA