"Counts as" grenades and thrown grenades

[Just_Me]

Title kinda says it all (and I'm sorry if it's been asked) but how does wargear and/or rules that gives a model "counts as being armed with xxx grenades" work with the rules for thrown grenades? Can they throw their "grenades" in the shooting phase as if they were the appropriate type of grenade or do they actually have to have "real" grenades to do this?

[Nabterayl]

Counts as is the same as having the real thing, unless an entry says it only counts as having grenades in certain circumstances (e.g., counts as having grenades in the assault phase, or when charging). Otherwise models wouldn't get the benefit of their "counts as" grenades even in the traditional assault phase setting.

[Tynskel]

Although, it would be fun for a screamer killer to shoot 2 blasts: 1 frag grenade, and 1 bio-plasma.

then chop chop chop!