Come to think of it, muffler is a box that usually sits bellow the exhaust pipe line. So, water can gather inside I reckon.
But, unless there's head gasket issue, once it's warmed up, the water should simply evaporate with the heat out of the exhaust end pipe.
Then again, most of the short runs we do, don't allow the muffler to get hot enough I reckon.
So, the water can gather inside.
What puzzles me though, it can't be that easy to create a weep hole into the muffler internal compartments without creating a exhaust soot
leak through the same hole. So, to me, it's kinda defeats the purpose.
My muffler has been going ok regardless of my welding filling of the "weep holes".
So, I reckon I did the right thing.
Yeah, it makes sense bike mufflers having weep holes 'cos they are upswept.
Then again, most car exhausts are down swept, and that's probably the reason I rarely see weep holes in car mufflers.

As Cuppa mentioned, it's look like I'm getting a good deal with this muffler anyway.
After repairing the muffler rust spotted leaks two years ago, it's still going. So, that's a bonus that I can't whinge about.

I reckon I should do the vacuum tester test of the intake straightaway and confirm there's no exhaust blockage or excess pressure.

Unless this particular muffler has a design to have that weep hole in order the balance the exhaust pressure as well, I should leave it alone.

Yeah, I think I'm gonna leave the muffler alone and give it another heat resistant silver paint spray to make it look new.