AFAIK yes, at least going by the wiki. Other characters have parents listed as Family: Unnamed mother if they've shown up before, but none of the Oomuro sisters have their mom listed yet, which I'm assuming is because this chapter is the first time she's appeared.
Boy, I've been away for a very long time from YRYR fandom and we still do not know who the heck is Nadeshiko's GF?? WHEN WILL BE THE RIGHT TIME!!! But after all these time I'm still #TEAMMEGUMI!!!!!