Nice collection! I really like that flat latch 36 and I am envious of your five screw 27. I have been looking for an early model 27 for a few years now and they just don't seem to turn up around here. M66 Smith's are hot on the market right now and I feel fortunate to have one myself.
The front sight on the Model 66 has been changed. They came with a stainless front sight from the factory. The good news is that they are available from various sources and are a drop in job to replace. A big plus is that it has what appears to be a factory 3" barrel. Right now the shorter barrels are the most popular and command a premium over the more common 4" barrels.
Here is a 66 in its stock configuration: