Is this water pump housing ok?

[Gilera]

I am replacing the impellor in my 1975 Johnson 115. It has the twin tube type housing. It is alloy so I assume original as I believe replacement ones are usually plastic. When I dropped the lower unit I noticed that someone has replaced the guide tubes with pieces of what appear to be black irrigation tube with threaded ends! These had stick to the tubes in the midsection and the threaded ends were crushed so they would have been pushing into the inside of the two outlets. The ?copper tubes running through the midsection still appear in reasonable condition. I was able to carefully bend the ends back into a round shape. One of the outlets in the housing has a couple of small pieces missing from the rim - see photo.
Questions:
Do the guide tubes just line up the copper pipes so they sit flush inside the inner rim of these outlets? I'm guessing this would never acheive a watertight seal unless there was a rubber seal in the outlets.

Is my housing servicable in its current condition? Perhaps a small repair with some jb weld?

Any suggestions for what I can use for guide tubes? I assume they just need to sit over the outlets to guide the tubes into them but not interfere with them joining.

[Gilera]

I understand a bit better how this is supposed to work now. The guide tubes need to be exactly the right diameter and have thin walls to sit just inside the housing but allow the water tubes to go through and be seated in the rubber seals at the base of the outlets. The ends of the tubes have been bent a bit by the previous persons failed attempt to use irrigation pipe. I'll try to make them round again without flaring the ends. Its possible that the tubes have been bent up too. I can't see the little pieces missing from the top rim of one housing affecting anything as it is well above where the tubes seal against the rubber.