Pato
I thought we were going to be friends, but then you mentioned you'd been riding a Harley Davidson.......oh well never mind

(only kidding).
My profile picture is of my GF Plunger and it's posted as a picture in:
http://www.audioworld.net/BSA/forum/index.php/topic,2991.msg20270.html#msg20270(If the link doesn't work I'll post the thread details)
I have no reason to believe that a '57 Plunger shouldn't look like that. I've owned it well over 30 years and I'm 99% certain that it was fairly unmolested (and unrestored) when I purchased it from a friend. I did put the single seat on myself, just for effect, but I do have the dual seat that originally came with it.
No doubt you'll find other pictures of Plungers on the site, but if there's a particular shot of the machine you want I'll just nip down the shed for you and post it on the forum.
I've currently got the top end off the machine (down to the crankcase) as it has been laid up for ten years and I wanted just to check things out. I've just received the magneto back from a rebuild so that's ready to go back on when I've got the time.
Have fun,
Brian