Will,
From the wisner site:
"In the sixties, C. Daly guns were manufactured by the firm of B. C. Miroku in Tokyo, Japan." We have however seen some apparently early guns marked Kochi, Japan."
This is the registered address of Miroku with the Osaka Securities Exchange.
Miroku Firearms Mfg. Co.
537-1 Shinohara
Nangoku-shi, Kochi 783-0006
Japan
Tel: 81/8/8863/3310
Because a spring interchanges does not imply any thing about the maker of the gun, except they sourced the same supplier for the spring. An entire receiver, trigger group, etc is a different story.
Pete