Touching the two leads, once the meter settles in it holds steady at .7
The owner's manual for the meter has specifications as to what it's designed accuracy error is. Never exact, Usually says something like a % of reading + or minus x number of digits. Your .7 measurement is what the meter lead resistance is and whatever circuitry the meter has internally up to the actual measurement chip. While it effects accuracy, that's not the spec for the actual meter measurement accuracy outside of it's connection method.
Accurate low ohms readings are problematic for inexpensive meters, and requires technique to gain meaningful results. To get real accuracy you need a wheatstone bridge. With that you can get pretty accurate resistance of nearly any circuit. I've even used one to locate short circuits, probing for the lowest resistance along the shorted circuit. Lowest resistance between two shorted circuits is the physical location of the short.
I would assume the numbers you are getting are not a huge concern for the function of the alternator assembly unless you think the melted area has corrupted the thin wire insulation between windings and allowed the coil wires to short together. Even if field coil wires are shorted together, reducing the effective number of coil loops, the system will still work, albeit with a slightly lower output due to the reduced electromagnetic field strength. The reduction will be in the percent of error you have measured in resistance below spec.
Your .2 reading out of spec. (assuming your meter has such accuracy) Would then equate to about a 5% loss in peak performance. Or about 7.5 watts less than the 150Watts rated. (If I've done the math correctly.)
Your call as to whether you wish to acquire a better field coil. But, I would measure prospects with your same meter to see if it really is an improvement over what you already have.
Cheers,
