Series 1 engine anomalies

[Marty ULC]

Have a series 1 with the original engine according to the Cumbrian archives.
First registered june 1959
The engine number starts 77...
It has the larger exhaust studs.
Later style crank and mag housing.
Groove for oil thrower washer.

If I didn't have a copy of the original registration entry I'd just have assumed someone replaced the engine with a later one.

Would it have been likely that these mods were made retrospectively or did innocenti make these changes earlier than is thought?

[Digger]

The frame number might be useful as the date of registration isn't a very good indicator of the age of the scooter.

Sticky states that an LI 125 SII engine has a number that starts with 7 or 8.

Given that SI and SII machines were both built in 1959 my bet is on it having been fitted with a SII engine from the beginning.

I'd also say yes to this "Would it have been likely that these mods were made retrospectively".