Transcript of a message I wrote to someone on eBay called Joe who sold me an alleged 67 wiper motor and pump assembly. This includes very nice pictures and description of what to look for:
Here is a copy of a page from the 1967 Camaro Factory Assembly Instruction Manual. This page shows the W/S wiper motor and pump assembly. The PN is shown in the top part of the photo, PN 5045508 for the MOTOR & PUMP ASM.
Following picture is a side-by-side comparison of the eBay assembly compared to an original assembly out of a 1967 Camaro. Note that the part # shown above in the factory assembly manual is stamped on the original assembly's motor cover, 5045508. Although the eBay motor cover seems to have the same overall dimensions, it doesn't have a part number.
Also apparent is the different washer pump assemblies. The eBay washer pump cover is block-shaped and doesn't have the unique and distinctuve 1967 "bump" which is clear in the photo of the original unit, and in the factory assembly manual above.
Here is a second picture of the two assemblies, side by side. Not only is the eBay pump cover a different shape, but the entire washer pump (underneath the cover) is different. Notice the difference in where the electrical prongs exit the cover.
Here, in the third side-by-side photo taken from the firewall side, you can see the different mounting plate shapes. The eBay assembly is on the left and the original assembly on the right.