Can anyone date this ammo?

[SaxonPig]

Remington .38 Special 158 grain round nose lead in the green and white box. No date of any sort on the box (but Kleanbore priming is mentioned several times)but the index number is 5138. My guess would be 1970s but maybe someone who collects ammo or is knowledgeable can pin it down for me? Thanks.

 

[Old Fuff]

I think it could be earlier then 1970. My memory says it was around during the 1950's and maybe before. On the other hand I'm not sure when or if it was discontinued.

One problem with handloading is that you don't buy a whole lot of the factory packaged stuff...