You are correct,,the Meriden pump is the Model (19) 15.
I'll correct my post, I had it as the Model (19)14.
AFAIK they never made a Model 14. They had a small single shot 22, Model 10, I believe.
I should have seen that as I had a nice deluxe Meriden Mod 15 pump at one time!

Meriden Firearms was gone by the end of WW1.
The US Govt backed conglomerate of New England-Westinghouse took them over some time during 1918 for WW1 production of I'd have to guess small parts. Much in the same way they took control of the Stevens Arms Co. (and I believe Hopkins & Allen too)

Neither survived after WW1.
Meriden bankrupt & never to return.
Stevens was bankrupt and the assets and factory sold to Savage Arms Co. in 1920.
Savage put the Stevens factory to use and continued to use the Stevens name.
Then Savage moved their orig Savage Arms/Utica NY operation to the old Stevens plant in Chicopee MA just after the end of WW2.