I'm convinced Admiral Marcus plays with his toy ships whenever his underlings aren't watching, so the order of those models need not always be strictly chronological...
USS is a valid prefix for at least three Trek contexts: United States Navy vessels (as seen in ST4:TVH), United Earth Starfleet vessels (as seen on a computer display in "Affliction"/"Divergence"), and United Federation of Planets Starfleet vessels with NCC registries (but the Raven was also given USS on a computer display despite having a NAR registry). It seems unlikely that the validity would be limited to those three cases...
SS in turn is just shorthand for "starship", and need not tell much about the identity of the vessel in question. I don't think SS has ever been part of actual Trek pennants painted on spacecraft, although it appears on assorted computer displays; usually, "essess" is just a bit of dialog.
What does XCV-330 stand for, then? If this is the registry of the spacecraft, we're apparently looking at a large number of ships with XCV-prefix registries (why else would the number be 330 rather than 01 or 100 or the like?). No need for all of them to be ringships, of course; might be XCV stands for "experimental somethingorother" and includes all sorts of bizarre configurations, only a handful of which are warp testbeds at all.
"XCV-330" might just as well be the designation, aka proper name, of the design, though, much like "Ryan NYP" is the designation for another craft in Marcus' lineup, and unlike "X-15" is (because that one indeed is number 15 in a series of X'es). There need not have been any other XCVs in that case - 330 might mean this ship is capable of creating 330 millicochrane warp fields or cost 330 billion dollars to develop. Or perhaps she is three times bigger than the initial XCV-110, but there never was an XCV-220. Etc.
Bottom line: not even this bit of information can be applied to draw any solid conclusions - there's always room for interpretation!
The one bit we can count on is the name. Everybody in Star Trek dialogue agrees that Kirk's Enterprise was the very first, even if indirectly (that is, they always say that there have been a specific number of ships, this number dictating that NCC-1701 was the first). This means that everybody is discounting NX-01 along with other known spacecraft named Enterprise. This presumably because those were "foreign" craft - we no longer can argue that the heroes would omit "lesser" craft as NX-01 is not suitably lesser than NCC-1701, either in physical characteristics (she walks, quacks and fights like a starship) or in status (she's called a starship).
Since XCV-330 is discounted along with NX-01, we could well argue she's "foreign", too. Meaning she's not UFP Starfleet. Which goes well with the idea that her picture already hangs on a wall before the UFP Starfleet is founded...
The other argument would be that XCV-330 is not Starfleet, regardless of which Starfleet, and our heroes always omit all civilian craft (and, on a separate basis, omit NX-01 as well, but this is merely an irrelevant additional detail). We could then place XCV-330 in the late 22nd century or whatever, the idea being that she was a pipe dream before Archer's days but was finally realized when Earth got its warp engine act together. We cannot conclusively identify the other picture on that stretch of 602 Club wall as an actually built spacecraft, after all (although she's likely to be a pencil of the NX test rig). Although we can identify a couple of other "real" craft there, such as the Phoenix or the DY-100.
Timo Saloniemi