Not quite. You'd have to unpack the distribution, compile gcc while making sure that the linker doesn't search in it's default location(s) (usually /usr/lib), but in those of the distribution, while at the same time making sure that the paths for said libraries do not derivate from the running distribution. Also, it's advisable to compile gcc on a system running the same Kernel version as the distribution and is not optimized for an other architecture.
More information can be found on the
Linux from Scratch homepage [0][1][2]
Besides, why do you want to use PLoP? As stated on the homepage, it's not really intended for new users but as a rescue disk. Other Live distributions are much more user-friendly, and most even come with a complete development chain.
[0]
5.5.*GCC-4.3.2 - Pass 1
[1]
5.12.*GCC-4.3.2 - Pass 2
[2]
6.14.*GCC-4.3.2
Edit: Quick question: did you even look at the homepage for PLoP? There's a whole entry on
adding new software