Yes and no, Go back far enough to when Titan was releasing the books in the UK, they had a different numbering to the US versions of the books and when S&S took over in the UK, the numbers jumped in the UK.
Yep. Titan kicked off their monthly releases with "Chain of Attack" (#1 in UK) but Pocket was only doing new novels "every other month" so, in the UK, every second release was a title from the Pocket backlist. It lead to a few weird problems, such as a JM Dillard original character dying in one novel ("Bloodthirst") but popping up alive in a subsequent title ("Mindshadow").
So there were 8 or so were numbered in the US but not the UK as they were released as Giant Novels (if memory serves)
The first three TOS MMPB "giant novels" in the UK were exactly as they were in the US - unnumbered - but, due to their positive UK sales performance, some older Pocket titles with a sufficiently long-enough page count, such as "Uhura's Song", "Shadow Lord", "Dwellers in the Crucible" and "Pawns and Symbols", came out in UK as extra