I was thinking the M38 was like the 2A with the motors on top and the M38A1 was like the CJ3A with the wipers on the bottom. But now I cant find a picture of either M38's or M38A1's with the wiper anywhere else but on top. The M151's on the other hand have them on the bottom. The link I posted below sheds a lot of light.

https://forums.g503.com/viewtopic.php?t=51770