Swing weight yes, as you are removing material from the over all club. Loft and lie no.

it depends if they're just 1 inches over length or if they were properly built for over length.

loft and lie you should be setting anyway, so don't worry about that, it's more a matter of head weight. though most don't seek lighter heads for over length builds and just live with the increased swingweights.

maybe find out where they were built and if there was anything more than just leaving them longer, if that's the case just cut 1" off and chuck on new grips, then set your desired lofts and lies.

Anytime you cutdown a shaft, you will change the flex, weight and lie angle a little. Is it noticeable, it can be. Will it have a huge impact on the club performance, not really.

If you are a x shaft player, getting a set that is stiff and an inch longer you will stiffen the flex a little but it won't exactly match a standard X flex, same would apply to if your an S player or R player.

The opposite is also true if you are an X player and bought X shafts and cut them down. It will play a little stiffer.

The loft of the club will not change as that is built into the iron but the lie angle will change as you made it shorter so you would need to flatten the lie angle to balance it back out.

Definitely lower the swing weight. You might have to add lead tape. Assuming the SW is already D2-D4. If it is higher, you may be ok once cut down.

1" decreases the swingweight by 6 points. They might be heavy to begin with or the previous individual may have had weight inserts in the grips to decrease swingweight. Check the swingweights first. D2 is the standard swingweight for irons with Lamkin standard grips and DG R300 shafts.

If you shorten a club by 1" you also have to increase the lie angle by 1*. Standard lie for a 9 iron is 64*. 7 iron is 63*. You need to hit the irons on the lie board to get the correct lie angles.

My irons are set -1/2" and 2* upright. I have Winn Excel RF oversize grips and they come in at D2. My fairways and 27 hybrid are -1/2" and they come in at D2. The fairways have 70 gram shafts, as does the hybrid. I have a couple weights coming from eBay for my 3 wood (I shortened it to 42.5" but it dropped the swing weight to D0; an 11g will bring it to D1 and I have a 14g just in case I go to a Bassara shaft). 3 wood is at A3. The 7 wood and 27H are A2.

My driver is 44" with a 60g shaft but I have a 15g headweight. I have it set at B3.

Dynamic Gold R300 or S300 iron shafts are 125g. Project X are 115g. That's a difference of one swingweight point. What types of shafts are on the 712MBs? A 95g steel shaft is 3 swingweight points lighter than DG.

Adjusting the irons 1" will decrease the playing lie two degrees- if lie wasn't adjusted for the 1" additional length when built then they are at Titleist's standard lie. In any event you should determine whether the final lie suits you.

When you cut the shafts 1" swing weight will decrease 6 points requiring 2 grams added to the head for each swing weight point you wish to add back.