The pronunciation of this character, and many others, is recorded in the same book.
In the following photocopy version the annotation of ⿰口⿻丅口 is legible, which suggests that the pronunciation is the same as 西:
https://commons.wikimedia.org/w/index.php?title=File%3AGGZBCK525_%E5%BE%A1%E6%B3%A8%E9%81%93%E5%BE%B7%E7%B6%93_%E5%8F%83%E5%90%8C%E5%A5%91%E9%87%91%E9%9A%84%E5%A4%A7%E7%BE%A9_%E6%B7%B8%E5%BE%AE%E9%BB%83%E7%B1%99%E5%A4%A7%E9%BD%8A%E7%A7%91%E5%84%80_%E6%A2%B5%E9%9F%B3%E6%96%97%E7%A7%91.pdf&page=347
On the same page of the CUHK version the pronunciation of ⿰口圖, ⿰口粹 can be easily seen:
IRG Working Set 2021v6.0
Source: YUAN Zhiyu
Date: Generated on 2024-12-05
Evidence
In the following photocopy version the annotation of ⿰口⿻丅口 is legible, which suggests that the pronunciation is the same as 西:
https://commons.wikimedia.org/w/index.php?title=File%3AGGZBCK525_%E5%BE%A1%E6%B3%A8%E9%81%93%E5%BE%B7%E7%B6%93_%E5%8F%83%E5%90%8C%E5%A5%91%E9%87%91%E9%9A%84%E5%A4%A7%E7%BE%A9_%E6%B7%B8%E5%BE%AE%E9%BB%83%E7%B1%99%E5%A4%A7%E9%BD%8A%E7%A7%91%E5%84%80_%E6%A2%B5%E9%9F%B3%E6%96%97%E7%A7%91.pdf&page=347
On the same page of the CUHK version the pronunciation of ⿰口圖, ⿰口粹 can be easily seen: