Re: how can you tell if it's a long or shortshaft
"L" in the model number indicates a longshaft
It should be obvious that there is a 5" extension piece between the gearcase and the exhaust housing (leg) if its a long shaft.
measure from the transom top ( or where that will be in the mounting clamp bracket) down to the anti-ventilation plate above the prop.
If that is a bit more than 15" ( betwixt 16 and 17") it is a standard shaft, it is a bit more than 20" (21-22") it is a long shaft.