'51' Aerometric Pencil Cap Question

[octatonic]

Hi All-

 

some time ago I fell in love with the Parker '51' Aerometric demi and now have a ...few I recently discovered that I really like the Aerometric pencils as well. I have a few and recently got a burgundy one. The band on the caps of all the others I have is a thin band, but this one has a wide band. I looked on here and on the web and can't seem to find any info on this. Just wondering, was it a choice at the time, or is it a particular year(s)?

 

Thanks for any help!!!

[pajaro]

Is there a date code on that pencil?

[octatonic]

There is, but it's really hard to read. Now looking at it with a loupe. it looks like (but is still hard to read) 5.5

 

Thanks Pajaro!

[NinthSphere]

I have a '48 fp & p set like that.

[octatonic]

Thanks NinthSphere!