It can also depend on how the gun was originally ordered, as some agencies may request the spurless hammer option.
For example, the CHP (here in CA) ordered their .40's produced with spurless hammers (supposedly because they desired that their officers not be influenced to try and cock their guns into SA mode for the initial shot).
So, while full-size models may typically come configured with spurred hammers, and compact models may typically come with spurless hammers, it may vary depending on the how the gun was originally ordered by the end-user.
On the other hand, I usually switched out the spurred hammers in my issued full-size 3rd gen's to a spurless hammer (as an armorer) because I can easily suffer hammer bite.
When it comes to selling used guns, it can sometimes be like selling a remodeled house ... in that the buyer may not agree that a modification, or some particular feature, is worth the same value as it may be to the seller.
Also, when it comes to the matter of spurred/spurless hammers on S&W 3rd gens', there's always the consideration of whether the hammer configuration is going to be compatible with the holster design favored by the owner (or potential buyer). I've got to replace a spurless hammer for someone's 4566, which they'd previously asked me to install to replace the factory sprurred hammer. They've recently discovered that a high-end leather holster they're going to use (thumb snap retention) doesn't work well because of the lack of a hammer spur fitting
within the thumb strap, providing the necessary resistance to disengage the thumb snap. (Good thing I kept their original spurred hammer for them, huh? Even though they originally told me they'd never want to have a spurred hammer.
)
