Ssh 60 Never Expect This

[feldgrau33]

Hello gents,

I got this unexpected acquisition for my collection. Sell by a local antique seller in here:

There's some darker green paint on it. Could it be, it'll be repainted with TNI color (dark green) but it doesn't continued?
Too bad the stamp is fading.
Is there any other possibility to determine how old and from what factory this helmet originated beside from the stamp?

And when i got this helmet, there's confusion in me. Because i never thought the TNI would be purchasing this one. I once saw a similar helmet but in relic condition sold in here. And my friend once saw the same helmet sold in Bandung West Java from the bazaar of ex TNI equipment.
Is there any possibility the Soviet would sell their new helmet for their future ally e.g. Indonesia? Especially in the years 1961-65? If impossible, i guess this helmet was purchased limited by the TNI during the New Order era (1965-1997) or after the fall of Soviet Union.
Thank you in advance.