^Really, and it is spelled as Temasek by the way.
Singapore was known as Singapura from around 14th century onwards. So yeah, if PoC takes place around 1720, then the country should be known as Singapura.
I didn't get a chance to watch the second installment, will probably try to watch it before the third one comes out. Chow Yun Fatt's "Welcome to Singapore" piqued my interest.