You have a four pin Spanish side lock, made by Antonio Madariaga (maker's mark IRU) in 1970 (proof year code O*1). Barrel weight is either 1380 grams or 1360 grams (photo not quite clear enough for me to read the number).

I've circled the pins:



Purely FYI, the number of pins, or what people will call pins, has no impact on the dependability or durability of the lock. OTOH, some folks have significant emotional attachment to the number of pins in a lock :-)
Hope this helps!

Last edited by Kyrie; 06/08/19 07:09 PM.