do these hoses run inside the mast channels?
or do they run outside the mast on one side?

figuring out how they run depends on what type of mast you have?
duplex or triplex?
how many channels does the mast have?
chances are the upper hose pulley may have broken and the previous owner did not know how to change it so he made this makeshift one?
i'm just guessing here :o/

need more details

aside from this you will need the mast group number before getting any diagrams on how the hoses are ran and get with komatsu for that information. Without the group number nobody will help you.
This number is generally stamped on one side of the outside channel (right side maybe)
it will consist of numbers and letters most likely
just look and record any numbers you can find stamped into it and call komatsu dealer.
They will also want to know how many functions the truck has like 3 or 4 functions, they may ask if it is a duplex or triple mast also. Generally the mast numbers should be enough though.