Well, with some quick and easy Googling, I found the answer here:
State by state breakdown of RTKBA provisions, and dates of amendments. As you can see, many, though some by amendment, added the "concealed carry" language early on. Kentucky for example in 1850, MS 1890, MO 1875, LA 1879.
IMO, this "concealed carry" issue will be the biggest hurdle. This could be an issue left to state or local discretion for regulation in the end, and if we get strict scrutiny, I'm not sure how that will effect it, if at all.
