Wanted - classic card reader "spring"

[Leviset]

Not having an HP-67 or HP-97 due to the horrendous silly prices asked (although I did have a totally dead HP-97 which many people kindly tried to fix - I eventually donated it to Valencia Science Museum!), I don’t know the size of the spring.
Would a spring out of (1) a retractable pen (2) out of a battery compartment or other sources fit?