7524258, 2920-752-4258, MS35909-1, 2243, AR5S, WR44, XMJ-14 all fit the M38
8357724, 2920-835-7724, 2920-00-282-9135, MS35909-2, 2245, AR7S, WR46, XMJ-17 all fit the M38A1/M170/M151 series.
Other than being a single heat range apart they (top row and bottom row) can be interchanged up and down as needed. IE if you wanted a hotter or colder plug.
Your 7525550 became 2920-00-752-5550 which then superseded to 2920-00-571-6731 which has the following spark plug numbers assigned to it:
2344 Spec'd for the M715 Kaiser 5/4 ton
8668752 Spec'd for the M715 Kaiser 5/4 ton
These are all 14mm x 1/2" reach which is too long for the M38/M38A1/M170/M151 series and I believe the barrels are sized differently so the M38 series cables won't fit in them.
I also noticed the 715 used the 2407 as well so the 2407 (Autolite power tip) would be the hottest plug for the 715 and the 2444 (Autolite non-resistor) the coldest for the 715.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C