You're correct that there isn't a number 4 Back Wynd. There are a couple of new houses, so perhaps No4 was demolished when they were built.
I live in Oldmeldrum, but I've only been here 23 years and can't remember a blacksmiths shop.
Your best bet is to contact the Meldrum and Bourtie heritage society. Here's a link to their website. -
http://www.oldmeldrum.org.uk/There is a contact email - alex.manson {--at--} tesco.net
Someone there will be able to help, I'm sure
Moderator Comment: e-mail edited, to avoid spamming and other abuses.
Please replace [AT] with @