Just had a dig through my old displays. There seems like a lot of interesting variations.
MkI/II:
1. Regular Monsanto (some using gold legs to attach to module, some using direct solder pads).
2. Encapsulated with each LED segment laid down individually. No DOW. No hanging LED dots underneath....I may have removed them though.
3. Encapsulated with discreet digit dice. DOW provision, but DOW segments not bonded. Hanging LED dots underneath.
4. Encapsulated with discreet digit dice. DOW provision with DOW segments bonded !! Hanging LED dots underneath.
The discreet die above would show 'R' in Friday as shown below in black (not that the module supports it).
MkIII/MkIV:
1. Encapsulated as Jeff showed. 'R' displayed as below in red.
2. Encapsulated with discreet digit die with DOW. 'R' displayed as below in black.
3. Exposed wire bonds + goo. Didn't look at carefully.
No makers marks.
Rgds.