Issue with appraisal

[Fred Krueger]

Just bought our first rental. A "duplex" in MN. The property is actually two separate structures on one lot. A 3BR and a 1 BR. Trouble is the appraiser couldn't find comparable properties because of the uniqueness (not a normal duplex). Not a big deal for us as we just got the loan value under $100K so the bank was able to use a "drive by appraisal". Essentially just quick exterior photos and we move on to close. Just wondering how big of a deal this may be in a decade or so when we want to sell? Anyone encounter anything similar?