1949 cab shackles

[Flysocal]

I got a set of cab shackles off eBay and they don't fit my 49 frame. The mounting holes on the frame are staggered. Like this:

Here is what I got off eBay:

As you can see the bracket that mounts to the cab is the same but the 49 bracket to frame is staggered. Does anybody have info on which years had staggered frame mounts and which years were straight? The repops are straight but say they fit 1949-1954 (not true!). If anybody has an extra set of shackles that will fit my 49 I would appreciate it.