"The SWR was 1.2 to 1 on 144.8 (Close enough) But could never get it to 1-1 anywhere on the band"
Dude, you're done, especially if that's a measurement up near the antenna not at the shack end of the coax. But either way, it's probably fine.
For all I know, the antenna is designed to have a 42 ohm input impedance which is close enough, period.
Getting 42 ohms instead of 50 could happen if you're off by a tiny, tiny bit in all kinds of ways, and in my opinion, it's almost certainly not worth the trouble to bring it down.
You can go ahead and measure some interesting things instead of SWR too...
Dowload Polar Plot from G4HFQ's site:http://www.g4hfq.co.uk/
Get your radio plugged into the sound card, turn off the AGC on your radio and and get someone close to key down for a minute while you rotate the antenna and collect a pattern.
You could build a simple dipole and put it on the other end of your roof facing toward a loud signal source and actually compare the gain of the yagi vs. the gain of the dipole (you can do that in Polar Plot too, just switch back and forth and you'll get a step change calibrated in dB )
Or heck, compare it directly against your quad!
This will tell you a lot more than anymore SWR reading will ;-)