In terms of value, I don't think a third fastener, standing alone, makes any kind of difference. I wouldn't ding an otherwise better or best gun pricewise for not having one. They more correlate to the standard features available in the era of construction and therefore represent what you would expect to encounter on an off the shelf golden era best, IMO.
My guns have the hidden one. I like that feature compared to a doll's head that develops gaps over time as the actions loosens. I was reading one of the big makers when reconditioning/rebuilding old actions actually take out the doll's head for that reason.
