Where to find cab-to-frame mounting hardware??

[BK'66Step]

Hi guys!!

The old rubber cab mount bushings on my '78 K10 were toast so I decided to replace them with ES poly bushings. The job, overall, has been significantly easier than i expected! However, I have found that the "sleeves" that the bushings slide on to are pretty rotten and need to be replaced. I found a kit that supplies the sleeve, bolt, washer, and new rubber but it looks like its backordered at least 2 months. Does anyone know where I could buy (or does anyone on here make) just the sleeve? Seems like someone with decent welding skills (not me) could make one... my rear cab mounts are fine, its just the front cab and the radiator support mounts which i believe are the same size. Any leads on these would be great!!