The 144 is the slim fountain pen of the Meisterstück line and can be identified by its cap alone: it has a slip cap without a thread, whereas the larger Meisterstück pens screw shut. So if there is no cap thread on the barrel, that is a reliable pointer to the 144. Pens of more recent production also carry a laser-engraved serial number on the cap ring; it is one of several marks of authenticity, but it does not replace an examination of the finish, the imprint and the nib. As of 2012, used examples were changing hands for around 100 euros, which was considered cheap at the time.
Posting the cap on the end of the barrel is a matter of taste and does the pen no harm, as long as no force is used. The cap should be pushed on far enough to sit firmly; if it will not hold and keeps slipping off while writing, it has merely been laid on loosely. Many nevertheless do without on the 144, because posting the cap makes an already slim pen tail-heavy and unsettled in the hand.