Hi everyone

It's been a long time since I've been able to get back to sorting my collection....Thus far I've been holding my questions until I become more educated, but this one has me stumped.
Is there any other way at all to see if this is USIR v/s USPS? The big fat S on the back is clear, but that's useless from what I've learned. Would be nice if it was the rarer printing, but I'm in doubt. I see the previous collector had it wrong on the back anyway as a 225, as it has triangles.
Thoughts? Thanks so much!

