Kheaiftouaw:
Ah, ok.
But in general ship shares are not specific to a certain type of ship. Just some benefit rolls give you more shares when you use them for a specific kind of starship.
Actually, that is not entirely true. Certain profession benefit from focusing their shares on a particular type of ship (Nobles -> Yachts, Scientists -> Lab Ship, Merchants -> Free Trader, &c.), where they get more shares (5 instead of 2) per benefit if they target a certain ship type. This information is scattered about in the Mustering Benefits sections (Core, pp.34-6).
The IISS is unusual in that actually get allocated surplus scout ships as a benefit, but do not actually own the ship. But the Scout Service also doesn't actually let their members retire. Mustered scouts are actually on inactive/detached duty. In theory, they can be recalled at any time. It does say in the Core Rules (p.35) that a Scout Ship benefit can be traded in for 1d6 other/generic ship shares.