Can these letters still be posted through that letter box, or has it filled up?

How to say “Can these letters still be posted through that letter box, or has it filled up?” in Japanese

In Japanese

このポスト、もういっぱいかな。まだこの手紙(てがみ)出(だ)せる？

Kono posuto, mō ippai kana. Mada kono tegami daseru?

Can these letters still be posted through that letter box, or has it filled up? in other languages