Yes! IIRC, RDP was originally based on simply sending over the GDI calls -- the Windows draw instructions -- directly.
I've been told it moved away from that as networks got faster, interfaces became more GPU-accelerated, and video encoding became hardware-accelerated, so that now it's not much different from VNC. But I don't know when or to what extent, or if RDP still uses any draw instructions at all.
RDP most likely uses privileged instrumentation to detect screen damage, rather than having to do a full framebuffer scan (or getting framebuffer damage bounds) to identify diffs.
Modern RDP can use hardware h.264 encoding if your GPU supports it, and grabs the output from the framebuffer and streams it like a game streaming app does. I think the default RDP mode still sends the draw commands the old-fashioned way though.
I've been told it moved away from that as networks got faster, interfaces became more GPU-accelerated, and video encoding became hardware-accelerated, so that now it's not much different from VNC. But I don't know when or to what extent, or if RDP still uses any draw instructions at all.