I remember most armour assets are Kostrad divisions.
I believe (if other Indonesian members can correct, please do), all Kostrad Tanks Battalions already switch from Scorpion 90 to Leo 2. Thus AMX 13 and Scorpion 90 right now mostly are in Kodam Level.
The open source numbers (Janes, Military Balance) suggest that operational ones are far lower.
Yes, from 60's to 80's all TNI-AD tanks basically AMX-13. Yes at period in 60's they operate some PT-76, but from my understanding is short live as all being move to Marines in 70's. One of the reason is the arrival of ex Dutch AMX-13 105.
From TNI-AD data AMX-13 come in two batches, 1st batches mostly AMX-13 75 directly from France in early 60's (#185). Then from dutch in mid 70's (#130). So even tough TNI-AD procured more then 300 AMX-13, but at most around 250+ operationally on the peak operation between 70-80's.
After that the number operationally continue decreasing with Scorpion coming and later on Leopard 2. Most that being withdraw are AMX-75 (but I still see few Kodam in Kalimantan and Sulawesi used them). Even that there's still 100-120 AMX-13 in operation (This is my estimation base on rate of replacement).
Unless the speed of production and procurement of Harimau MT increase, it will need 8-10 years to replace them all. This's basically with conservative estimate of 12-18 annual production capacity in Pindad. That's mean in my calculation at least there's a need to retrofit 30-50 AMX-13 105 (or 2-4 companies), as stop gap.