Usually, yeah, but not necessarily (e.g., for those with dedicated IP addresses). Even then, it usually will be since most customers will just add the (custome

Usually, yeah, but not necessarily (e.g., for those with dedicated IP addresses). Even then, it usually will be since most customers will just add the (customer-specific) "include:nnn.wl.sendgrid.net", or even just "include:sendgrid.net". But, for whatever reason, I've come across several that add an "a:" or "ip4:" for their dedicated IPs instead (I assume there's a good reason for that, but I don't know what it is).