Hoyt Buck produced the first Buck Knife in 1902. Hoyt and his son Al moved to San Diego and set up shop as H.H. Buck & Son in 1947. Al Buck revolutionized the knife industry in 1964 with the infamous Model 110 Folding Hunter. The company's innovative history and attention to quality have made for many great collectible knives.
I guess I am confused on your meaning of 'Build Out'. Buck, has issued several versions of the models listed with stag scales. Sometimes with standard steel and bolsters and some with other types of high grade or 'non-standard' steel or metal. Sometimes a company such as Cabelas, Bass Pro Shops or Smokey Mountain Knife Works will make a special order and have those models with non-standard bolsters or blades with stag scales.
To me the term "Build Out" is associated with knives built with parts from discontinued models or ones from factory close downs. Sort of left over parts that are 'built out' and sold to public. This was the case with the Camillus factory close down, several individuals that worked at Camillus bid on bins of parts at the factory auction took them home and assembled them. Most were Camillus workers who had been making the Buck contract models in there normal work. As a collector, I consider these to be Buck knives and should not be looked down on.
The models you listed were never contract models but only built by the Buck factory.
I've seen a few Bucks advertised as Build-outs; the first Buck 302 I saw was a build out sold here in an AAPK store - as I recall the part number included the letters BO. I thought they were either short, prototype runs or parts clean up runs. Those are my impressions, not guaranteed facts. OH
Deep in the guts of most men is buried the involuntary response to the hunter's horn, a prickle of the nape hairs, an acceleration of the pulse, an atavistic memory of his fathers, who killed first with stone, and then with club...Robert Ruark