He seems to be referencing Eyepieces more than Scopes. None of the scope ovals that I've owned used BLUE Lettering. They used BLACK -- like my 1964 Sears 6336, So... maybe JTII used alternating ink color for different years; or, different ink color for the export type (scope vs. accessory); or, they used whatever color the sticker printer had on hand...
Also: Some of the older imports had both a JTII Sticker on the Scope, and a JTII Badge (circular paper disk) inside the case -- on its reverse side, a LETTER + up to 5-digit number. The Letter correlates to year made (B being older than F, and F being older than M, for example).
Stephen has a huge dataset -- a folder for each old scope containing pictures, copies of receipts, etc. -- and spent years verifying dates. An amazing amount of work! Anywho, I have to defer to him on JTII stuff. But, I will add the pix & info from Blake Andrews' thread to the Registry -- the more info, the better!