Elusive #554d ?

So many A157's..... 2cent Carmine

Need an opinion and very much still learning with Scott's, internet identification specs. and your help.

Not sure about what this is and have searched Scott's pretty thoroughly.
Could this possibly be a #545d or 599/606? Scott's says 545d has a natural smooth left edge--this has both verticals smooth. Is this a 'funky' coil or something?

Stamp shown:
Perf: 10 top and bottom, smooth edges R and L.
Frame: 19x22mm (maybe 19x22 1/4mm)

thanks again.
Bob+

Scott 606 rotary coil.

I have a few that are perf 10 on top, but they don't have a straight left side, they're perforated all around. Should I save them?