New Type 99 - Worth Fixing Up?

[Patrick Chadwick]

If I can fix the issues with the follower and lip in the receiver,

That kind of thing is basically sheet metal work. Should not be a great problem.

is it worth trying to bring it back to original spec,

IMHO only if
a) you want to use it as a shooter in a service rifle competition, or
b) it has a personal/sentimental value to you beyond its market value, or
c) you enjoy the challenge.