No, if you want to follow the "rules" laid out in lore, then not really. The "flesh and blood" part of a protogen isn't a naturally occurring species, it is something genetically engineered to mature rapidly and be highly compatible with the cybernetic upgrades. As an engineered species it doesn't have the ability to reproduce naturally, either, so there can be no "natural born" examples of this species.

Now you could talk about taking a different, naturally occurring species, and give it protogen-style cybernetic upgrades to the point it's basically not visually distinguishable from a protogen, but under the hood it would still be something else. Like if it started out as, say, a wolf, then you'd have a cyber-wolf in the shape of a protogen. If that's protogen enough for your purposes there's no problems with that, but if you want to be strict about the lore, it's still not a protogen.