I have to agree, that the asphalt/gravel jack would be a pretty nice find. You say this catalog is
newer than anything you have? I know you have some pretty amazing tool collections, so I'm pretty sure that your jack catalogs are nothing short of amazing as well.
I'm constantly seeking and trying to gain knowledge about these great old American jacks. Since there is very little to no information about old floor jacks on the internet, these catalogs represent a great resource for me. It's very frustrating that they just seem so difficult to find. I'm pretty sure that older catalogs must have gotten tossed away in the garbage as newer ones replaced them.
With the catalog you posted of the SJ-18, I was able to confirm as told before by an older gentleman, that it was indeed available with optional rubber wheels. I now see in this catalog that these Walkers had the same option. I recently picked up another Blackhawk catalog, and was shocked to see that an S-4 was also available with rubber wheels.
http://garagejournal.com/forum/showthread.php?t=114011&highlight=blackhawk
I don't know the model of this jack, but now I can say that I've seen an old floor jack in a picture that actually has a set of rubber wheels installed. This is quite an accomplishment for me....
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=290602080904