They'll probably be random which is why I just saved the eBay search so I can get alerts when something new shows up.
I'm sure it seems picky to care about the grenade size, but it's something burnt into my mind with T2, I think of those grenades and just looking so huge, the Cyberdyne gear was about excess, big ass gun, big grenades, just totally destroy anything in his path. The 1/6 M79 grenades out there just don't have that same intimidating look. Even on a slimmer figure I think they'd look too small.
I would think that if the ones Arnie has in the movie are standard M79 grenades, then 1/6 versions should look as big, unless they're scaled down to fit in the launcher. I would rather HT not build in this feature and just have a nice launcher and proper scale grenades, but I think they'd go for the toy factor of a launcher you can load.
The Sideshow PF grenades look great, I'd love that in 1/6.