I think most kits in Airfix's "Smithsonian" series were just reboxes of some of their other kits.
Their 1/72 F-14 Tomcat was released in normal boxing before it was released in "Smithsonian" packaging. It was good in its day (early-mid 70's) but takes a lot to hit today's standards.
I'm not familiar with the Airfix Apache, but I suspect, typical to Airfix, with the right research materials you can get a good representation of the real thing out of it.
As for collector value, I don't suspect it would have a lot, Apache kits were a dime a dozen for several years, it really got popularized after the film, "Firebirds" was made. The film stunk but the Apache got quite a lift in popularity, just like what "Top Gun" did for the F-14.