150mm is the actual bed width. And i have pribted right to the edges on my rep clone (amost of these enclosed boxy style printers are based on the original makerbot replicator - if you want to know if it's a rep clone. Look at the print volume. usually 223-225x150x150 - or numbers really similiar to that).
So yeah - you should be able to just about squeeze a 148mm print on to it.
worst caes scenario you slice it in half and print two 74mm parts and glue them to gether.
Flashprint lets you do that.
But better to do it in a cad package then you can add interlocking joints to insure the two parts match up exactly.