Thank you both, very much.
I was surprised, after so many years collecting, a postage stamp would defy
a Scott identification.
Seems I was justified, as the stamp in question is still not addressed in the Scott catalogue.
Completely missing !
A set commemorating the 75th anniversary of the Universal Postal Union followed in December 1949 (Scott 62-69).
No, the 15 sen stamp does not appear in this list.
Apparently Scott #331 = SG572 (last issue under Dutch Administration).
No, There is no Scott 331 or 332 listed (332 being the 25 sen blue)
Those numbers being strangely absent.
(Scott goes from #119 thence to #333
I presume the missing numbers may be a specialised tome.
I'll now look up Mr. William Steiner, see if he has afforded a space for these two orphan stamps.Note: Cannot see any spaces afforded by Steiner (Pages designed by Rick Scott)
These are really orphaned postage stamps
(due respect to Yvert and Michel for their inclusion)