No problem. As I said it worked for me and I had a huge pile of dirt/leaves blocking my evaporator coil and getting almost no air was getting past all that to my vents.
Be especially careful with the wiring and sensors because obviously hard old brittle wiring and connectors break easily. But you can pry the top of that plastic box open pretty firmly, I had mine pried open so wide and with such force to the point I thought it might crack. But I needed at least 1 - 2" clearance to do the job so it had to be done. In the end it was fine and no damage occurred to the box whatsoever.
I figured it was worth the hassle to get that evap clean because even if the lid cracked or broke I could always just silicone it back together. Good luck.
A second place to clean/inspect is inside the squirrel cage (blower fan). Remove the passenger front fender and set the climate control settings to fresh air (to open the fresh air blend door). At this point you can see right inside the squirrel cage and part of the intake venting. You may be in for an unpleasant shock: my squirrel cage fan had a very large plastic grocery bag trapped inside it and that obstruction ended up being a big part of of my air flow issue! I've heard of squirrels and other rodents making nests in there too