The caps were added as basic protection against a common splitting problem when the fore stock was smacked against a hard object, this happened a lot. They were also made without caps well into 1946. They had massive quantities premade and wanted to use up existing stocks.
Condition is everything. The original quote is pretty close. A pitted, dinged, rode hard put away wet rifle, as long as it's complete will bring $200. Maybe $250 if it's all matching. Usually this is classed as good. In very good condition, the No5s will vary between $250 - $400. Again, depending on condition and matching/non matching numbers. In Excellent condition not mint or unissued the rifles will range from $400 - $550. New unissued specimens, still in grease and unissued will go as high as $750+.
Condition, condition, condition is what it's all about. No5 rifles aren't rare by any means but they are a lot fewer in number than No4s. A minty, unissued Savage No4 MkI* will go for $500+ Long Branchs' a little more UK No4 MkIs' in minty condition will bring a bit less. All of course depending on the buyer and in many cases the economy of the area. For person making minimum wage, a milsurp is no longer a cheap way to get into shooting. Even the cheap com bloc stuff can be a stretch on many budgets. Then of course, there is the ammunition to feed them.