I picked this kit up before you posted your review, Russ. I also had high hopes for its detail and ease of assembly, but was very disappointed to see the wings of the F6F-5N instead of the F6F-3 inside the box. I immediately wrote to Dragon Care and included a pic. They said they would look into this.
You're right ... the instructions do not call for removing the cannon ports. In fact the instructions show wings with smooth leading edges. Correcting this through surgery on a small, $40+ kit is ridiculous.
Mounting holes for rocket rails are also present and while this would've been a feature for F6F-5s and F6F-5Ns, it was rare on F6F-3s. Puttying these over is also an unnecessary step for a model with such a big price tag.