If you look at other stuff from the author, there is yuri there, so it's still a possibility for this series!
I'm frankly not "worried" (if such a thing can be applied to manga predictions). Like I said, I think this will end similarly to Amber Teahouse, with Matsuri working for the book store permanently, or otherwise doing something related to literature. And there isn't even a hint of either of them being interested in anything else, so it all seems in the clear to me ...
Of course, whether anything actually happens can't truly be predicted. Japanese like their open ends, even if somewhat less in anime/manga than in literature. But it might very well stay somewhat ambiguous. And there is obviously also the danger of it getting canceled for not being some generic harem rubbish and getting a random crappy non-end.
But I don't think even then I'd care much. They are cute the way they are. This is not a read I expect any fast-paced developments or dramatic twists from. It's calm and slow-paced and good as it is.