Here is some information about the Moretti company- it was founded in 1911 so there are no pre-1911 Moretti beads. Their heydays for beads for the African trade were the 1920s.

A quote from the book Ercole Moretti by Gianni Moretti -
"The millefiori beads produced by Ercole Moretti in this decade (1920s) are absolutely distinguishable from other beads for the accuracy of the placement of the murrine, for the choice of color and above all for the impeccable polishing."

Moretti beads with a high gloss finish are easy to identify. The glossy beads were normally made for trade outside Africa. The other distinctive surface for Moretti beads is a very smooth "eggshell" finish which is easy to ID on larger beads but not so easy on small beads.

Images of Moretti millefiori beads indeed show very precise placement of the murrine, most of the time. In this picture from Venetian Glass Beads by Giacomo De Carlo, the murrine have very distinct borders, except for the two highlighted with arrows. In the second picture, I've shown a strand with round, mixed mille beads. Some of them have these more precise borders, especially borders in white, but many do not.

I'm not sure it's possible to exactly identify Moretti beads of this kind. If I find out anything more, I'll post it.