The English translation of 1Q84 has used the translation by Brian Reeve. Here’s a passage from 1Q84:
The Gilyak is of strong, thick-set build, and average, even small, in
height. Tall stature would hamper him in the taiga. [“That’s a Russian
forest,” Tengo added.] His bones are thick and are distinctive for the
powerful development of all the appendages and protuberances to which
the muscles are attached [...]
Reeve’s translation of Sakhalin Island (2013 Alma Classics edition from archive.org, but there’s also an older 1993 edition):
The Gilyak is of strong, thick-set build, and average, even small, in
height. Tall stature would hamper him in the taiga. His bones are
thick and are distinctive for the powerful development of all the
appendages and protuberances to which the muscles are attached […]
I don’t have any information on the Japanese original.
Murakami’s Russian translator is a guy from Sakhalin, Dmitry Kovalenin. In the interview to P&I journal he says that Murakami visited Sakhalin at his invitation and later used this experience in 1Q84:
Да, в дороге Мураками читал «Остров Сахалин» Чехова в японском
переводе, работал с текстом, делал какие-то пометки.
And on the road Murakami read Chekhov's Sakhalin Island in Japanese
translation, worked with the text, made some notes.
So it’s plausible that Murakami’s included excerpts from his own copy of Sakhalin Island.