How to confirm I received the 915Mhz version and not the 868Mhz version

[WhiteHare]

The markings are silver vs. grey, which are subjectively similar.  Aside from that, how can I tell?

[Felix]

They are the same. Long ago I used grey paint, now I use silver markings. The hardware is the same, 915mhz.
You can use that radio at 868mhz without any significant degradation in performance. I only carry 915mhz, not 868.
See the transceiver guide.