"Sprig".....I know that when I replaced the Norcold with a Samsung, the Samsung was actually lighter. Even the propane refers were bolted/screwed in. Hopefully, you've secured the base of the refer with bolts/screws. I've done three of the residential refer installs and found that securing them at the top really locked them in.
On the three I did, I screwed a large tin plate (6" x 6" surface area attached with sheet metal screws) to the back corner of the refer that protruded about 1" above the height of the refer. Once the refer was in place, I went on the roof, removed the refer vent and ran a 1" x 1/8" piece of aluminum stock from the plate I installed to the framed opening of the refer vent. On two of the coaches, that frame was aluminum. Once the top was secured, the refer was rigid.
I'm guessing you installed the new refer in the old cabinet. You would have to be involved in a pretty good accident to get the refer to break it's mounts and bust through the cabinet. If you were in such a crash, the refer would probably be the least of your worries.
