The problem with dating such items as horse tack is that some of the more popular bits haven't changed remarkably over the years...as you see it may have a age anywhere within a range of 150 years or more...pick one
I have a similar bit and the model was most likely was made by (numerous) different manufacturers. The grasing bit also is made with fixed sides with drilled (or punched) holes for rein attachments.
As a side comment, I have seen sheep shears being sold in antique stores for $20 and up, and the identical model is still sold new today for maybe $5 bucks...