I would think that "ImportPart" would work. So you could pre-create your arrow, then have a script call it with importpart and you could use it as needed.

Try this arrow. Then in MoI, hit tab and type ImportPart. Navigate to this file and test it... Of course, this has you navigate and select the 3dm arrow file, but I think a script could hard code the file so just the shortcut would produce the arrow to orient and place. There is also "PastePart" which will provide the orient and place, if you have it on the clipboard already.