History Question about aluminum slotwheels

I found a set of 15x7 aluminum slotwheels ,not unilugs,5 on 41/4 lug pattern,the only numbers or logo at all on them are 15x7 R.I. The guy I got them from has had them on a Fairlane for a long time. Has anybody had a set of these or heard of the brand?

 

RI...is Rocket Industries...

 

Thanks

 

And thats a 5 on 4 1/2" bolt pattern.

 

You are right 5 on 41/2 need to read my own writing before posting.Do you know when they started making wheels?

 

Here's a great thread on the aluminum slot wheel by a great guy http://www.jalopyjournal.com/forum/showthread.php?t=363978&highlight=aluminum+slot