Wiper Motor Seal

[John Pasinski]

Hoping for some information. The attached photos came from a post by vendor Wes Hepp.
I think he sells these, but I haven't received an answer from him yet. I need to know if this is a grommet type seal that is on the exterior of the cowl; or if it's on the motor under the linkage arm. It would help if someone could tell me size also.
I need the wiper motor mount screws too. Having great difficulty locating a vendor for those. The thread pitch is 8-24 but it's a weird style. I may have to plug weld a 3/8 nut to an 8-32 flat head screw to make a reasonable copy. Don't know what else to do. Late model chevy wiper motors use metric screws which don't fit.