I have the makings of a 28/29 roadster pickup. I have an original cowl, quarters, and doors. I need a set of subrails. I met a gentleman that has a set of brookville subrails that came with a bunch of parts he bought. How can I confirm that they are 28/29 roadster pickup subrails and not closed cab subrails? Is there anything obvious or does any one have measurements that I can reference? I just don't want to buy something that I can't use. Any help would be greatly appreciated.