Czechoslovakia 1920 Masaryk Issue

This issue exists in three values and has a Scott notation that the imperfs "were not regularly issued". Finding this one value on piece, with a 1921 postmark, does lead me to ask whether or not this series and others with a similar notation were available to the public and if they could be used on correspondence? My presumption is that the cancelled ones are most likely "philatelic" in nature. One stamp collector to another, as it were.

Nice find you made. On the issue below:
Postage stamps used

Stamps of 500 and 1000 h were used to pay for parcels, for parcel guides, often in combination with stamps of other editions.
Exceptionally, 1000 h of a stamp cut in half in the vertical direction were used (Hubenec, Košice). Due to the high values, we usually find these marks on money (valuable) letters. Stamps were also used to pay for heavier shipments abroad.
Stamps of 125 h usually appear on letters as a recommendation surcharge (registered letter).
Similar to the unissued 25 h stamp (Hrad#269;any) in ultramarine color, the 125 h ultramarine stamp was also used seldom to pay for shipments.
Stamps imperforated, not officially issued, used do not appear.

http://www.tomfijala.cz/csrI1918-19...920/P140.htm

Thank you perf12. Exactly the information that I was looking for. I think that I shall most likely stick with my unconfirmed guess that it was a collector to collector mailing.