Let me take a stab at it. But first, I only speak for Guatemala stamps and share with you the words of Col. Romeo Routhier (deceased c2000). Col. Routhier lived in Guatemala from around 1950 until his death and was an expert on Guatemala stamps. His collection was phenomenal and he claimed to have every Guatemala stamp issued. I saw his collection and his claim was, to me, certainly believable.
I experienced uncontrollable drooling when I would visit him and see his collection.

He was the Scott catalog representative for stamps of Guatemala. He told me that Scott's catalog numbers are the most accurate and complete and up to date of all Central American countries. At least until his death. I don't have a Scott specialized catalog, so I cannot tell you what's in there.
In the "regular" Scott catalog for issues between Jun 13, 1921 to Jan 14, 1922 for Guatemala, there are only a few regular issues (no airs, registered, officials or postage due).
Listed are September 1, 1921: # 172-174. Also in 1921 (no month or day) are #175-177. No Jan. 1922 issues are listed. That's it, just 6 stamps. Now we wait to see what a Scott specialized catalog may have listed.
Marty