puleddu wrote:

I read that the various versions of Olivetti Lettera 32 have been shipped in two different "font" configurations.

I'm sure the Lettera 32, given its long production lifespan, was manufactured and supplied with more than just two different typefaces.

puleddu wrote:

One named Pica and the other one named Electo (the latter being more dense in the page).​

​Pica isn't a typeface, but rather a type size (specifically it would result in type that was 10 characters per inch (cpi); however, there were also variations of pica size type that were slightly smaller and larger than that). And when you say "Electo", are you sure you don't mean 'elite'? Elite is also a size, not a typeface, and it measures 12 cpi (again, there were variations, but 12 cpi is the norm).

puleddu wrote:

A guy who was selling one of those told me that there is a small digit between lowercase and uppercase symbols in every hammer, but he didn't know which number related to which font.

I'd have to examine all of the Lettera models that I own, but of the two that are on my desk at the moment, the pica model has "DP" on the type slug, and the elite one has a "3".

puleddu wrote:

Does anybody know what would make me recognise which font is used in the machine? Is there a code somewhere or a number to look for?

Only the identification number on a type slug, or a type sample, would let you identify which typeface a machine is fitted with. However, if you want to quickly determine its size (pica or elite) you only need to look at the margin scale at the back of the machine. Machines with elite typefaces will have a scale from 0 to 100, and pica fitted machines will have a 0 to 90 scale.