um. gregs45s, the best that can be stated is "by no means necessarily". . .
*anything* may be true - in some cases, an edition of a book bearing multiple countries' / territories' prices is known - or very strongly suspected - to've been distributed in none of them; in others, in only one or two of them; and in more than a few, editions bearing only one country's price printed on their covers are known to've been legitimately distributed in other countries, sometimes with the local distributor's recognisable price label upon them, sometimes with another publisher's price label upon them - and in one major fuck-up by two major publishers (one merkin, one british, albeit sharing the one merkin owner, times mirror of los angeles), tens of thousands of copies openly distributed in the yuk-of-gb-&-ni bearing the recognisably-logoed price labels of the uk publisher distributing them, where the merkin publisher did not own nor had licensed the uk rights from the authors or their agents.
it's much safer to flag a publication by a yuk-of-gb-&-ni publisher as "uk", and one of a merkin publisher as "usa", unless one knows the publisher in question actually had (at the time of publication) a subsidiary or sister company in a particular country or "territory", *and* that that (or those) companies co-published the edition in question.
(i know offhand of one^W two such examples for certain - i'll look them up and give details here as soon as i can find my copies, or recall the other's precise title, author, etc.) (one's "final stage", an original anthology edited by barry n. malzberg, the paperback of which penguin usa produced, and they and penguin uk co-published; t'other's a beautiful collection of b+w line,-drawn, c. 80% coloured cartoons by mary leunig that penguin australia originated, and they and penguin yuk-of-gb'n'ni co-published: see "there's no place like home".)
Couple more scans added.What's the score when it comes to "International"on books?(forgive my ignorance;),i see many books which have both a UK and US prices for instance,does that mean that this same book for example,was issued in both countries,even though the details on the back (web address etc) only apply to the UK?,or would there be a separate US printing,which also utilised the same ISBN/Barcode?.