Notice how the model numbers that it fit list MC-E50 series, MC-E400 series but not MC-E500 series.
The 500 series came out in 1995 and replaced the earlier 50 series. The fact that these bags list the 400 series but not the 500 series would imply that these are from very early in the production run of the 400 series, pre-500 series. My guess would be mid-late 1995.
Benny, all Panasonic bags fit all their uprights. There was no difference with the dustbag from the 41/42/43 and 44/45/46 models. Earlier models came with a reusable bag and plastic slider, but that was fizzled out by about 91/92, likely around the same time that the 44-46 were launched in early 1992.
Turbo500, I know that the same bag fitted all the cleaners but the only reference I made to it was not knowing how old it was. I genuinely appreciate what you have told me but I am confused to which aspect of what I wrote it applies to.