Have you asked McMaster Carr for that info? By my experience they will help in such things; they seem like the best run of the online suppliers (NewEgg used to be similarly good - then it got sold. Sniff.)
I haven't had maker's part numbers work well either. I ordered a small gear box from a long-time maker of small gear boxes. It apparently arrived on a Friday and the shop guys were in over the weekend to install it on a handling fixture. Monday I hear complaints about the engineering, but "they made it fit." Before ordering or even using it in the design, I had called the company who made it to ensure it was in stock and still good. I looked at their catalog and it looked like I wanted, with a cast body with four mounting tabs. I went the factory. It had no tabs - nada. So I called up to ask and they said - Oh, you need to order the mounting feet, an option not in the catalog. Apparently they changed the design, kept the old number for the new configuration and called it good. &*$$#$@#$%!'s
I also had an LED supplier mess with me - years after the gearbox and I'm still cautious. So I go to the LED website for a panel mount LED. It has a suffix for color. I call them - is this a panel mount and will this suffix get this color? Yes and Yes comes the answer. Off to purchasing goes the design. Get a call from purchasing - the number is wrong. I ask how is the number wrong; they say the website gives a different number. Search the website for the other number (feel mild stroke coming on

on different pages they have the same item listed with different numbers. Call the LED maker again - both numbers work; they are just changing all the numbers and the website has not caught up. @#^&*^@#%&^!@#^@&!'s This was fixed by calling procurement and saying it's all good and biting my tongue that they didn't call the supplier before dumping on me.
In contrast, McMaster-Carr only bruised me once - ordered 4 casters from them. They arrive. Three of one color tire and one of another color. It's for a deliverable test cart so functionally, no problem, but still. For some reason it seems like the pivot locking method was different on one of the same three color tires. I'm thinking - how big a box of these do they have in their warehouse that it's too hard to find a set of four? Since tire color wasn't an option ... Like JStephen said, it becomes $100 worth of phone calls to get a $10 part.