Are calligraphy works without Qin seal valuable?

About this question, but that calligraphy was written by a famous person, and its history can be identified, if it can be proved. Then there is calligraphy, which is valuable. The premise is that the calligrapher who wrote him is also quite famous. Of course, if the seal is missing. Then, the value of calligraphy will be reduced to a certain extent, but it still has certain value, and it must have historical precipitation.