The first one (E5XKBM10410) is a BTC 51xx, decent for an OEM rubber dome. You are right that non-stabilized keycaps can be used on other MX-compatible keyboards, but they look rather lasered than doubleshot to me. Useful only if someone needs that specific national legends, or as temporary keycaps for some experiments or something. Worth basically nothing IMHO, perhaps if it were NIB… or doubleshot.
The other (AQ6MEMB-74004) is a NMB keyboard as the FCC ID says, and there's also the part "MEMB", which makes me think it's a rubber dome as well. These usually aren't bad as long as they aren't too filthy and heavily used or damaged. However, they're barely worth anything (resale value).