The callnum,wrdl search works as is as long as there are no spaces. 920/M69b pulls up that call number but also 920/M69ba and 920/M69bi which is acceptable. But a search in our catalog for Series 21 pulls up "Series 410/Roll 2164" as well as "Series 21" and "Series 21/Yazoo County"
another patch was created for sn to search as phrase, to search as exact it would have to be ext instead of phr, but ext did not give us the results we wanted
There will be 2 new preferences in 3.12 to control if wrdl or phr are used for searching call numbers and standard numbers from staff and OPAC.