Gentlemen,
Lets remember that we are discussing Spanish guns, Spanish gun catalogs, and most importantly Spanish gun makers.
In the 1940s (and to a lesser degree today) when a customer ordered a model Something-or-Other (in this case a SEAM model 5000 Gran Lujo) that was the start of the conversation rather than its end. The customer also had the option of specifying the barrel length, cartridge, chamber length, final weight, stock type and dimensions, engraving pattern, and type of locks used.
H&H pattern locks were the most popular (and generally the least expensive), but there were many other choices available including Purdey pattern locks.
This is why actual guns of some specific model may differ sharply from the catalog description of the model, and from other guns of the same model. The catalog description is what the gun maker will usually produce if the customer does not specify otherwise. Actual guns of a specific model will be whatever the customer and gun maker agreed upon. That's why an ad for a specific model gun may indicate Purdey locks, but a specific gun may have H&H locks.
On topic, and moving into the realm of shotgun porn, here are some pics of a Victor Sarasqueta:
