I am not an expert and cannot say any thing about certainity, however little blow by is not a problem. My 1kz has same blowby as it was 3 yrs ago, and engine is really strong. Many mechanics suggested me to overhaul and many other things. I calmy reply let it be like that. I feel no difference in power it is as same as 3 yrs ago.
Dont expect no blow with such an old engine.
If btw blow by is due to faulty ege valve, it is not that costly. and some people blank that egr valve off. I am not sure if blowby can occur due to faulty egr valve.
Try towing some other heavy vehicle to estimate the strength of engine in Lahore, or try towing some light vehicle first and then some heavy vehicle just to estimate the strength by comparison. With 136k milage and if its been kept with care, and from your description i don't see any problem.