Pontius, you know more than me.
I passed through Biak first time September 1975 clasping a four month old maintenance license. I saw only two parallel runways at that time. I went straight to the swamps so had no time to look around. After a few months I did a bit of ‘looking around’ but more for the old Japanese coral cave that apparently had 600 men trapped and burnt out with aviation fuel, but that is digressing.
At another airfield, at Tarakan I did see plenty of old Russian equipment, helicopters and old radar pushed into heaps in the areas to the side of the airstrip. Maybe the change in military power at that time meant no spares were coming in to do necessary maintenance.
Ref TU-16 I have no knowledge but do question your dates.
West Papua was annexed in 1969, so it would not have been Russian or Indonesian aircraft if your dates are accurate. I worked several times with Indonesians that had been trained in Russian military institutions and would answer that if the bombs could have been fitted, yes. The men at that time were a better tradesman than is available now to the Indonesian military. They were capable of thinking as an individual without asking outside opinion and quality of work was excellent.